1. Field of the Invention
The present invention relates to semiconductor device fabrication.
2. Description of the Related Art
Some modern semiconductor chip fabrication processes include positioning a substrate on a pedestal and rotating the pedestal during the processing of the substrate. Positioning of the substrate on the pedestal and removing of the substrate from the pedestal is generally performed using robotically controlled movement of an end effector device, where the end effector device is configured to interface with a bottom surface of the substrate. To avoid damaging interaction between the end effector device and the pedestal, it is often necessary to provide a vertical displacement mechanism by which the substrate can be received from the end effector device at a location above the pedestal, and by which the substrate can be lowered onto the pedestal after removal of the end effector from beneath the substrate, and by which the substrate can be raised from the pedestal to allow for positioning of the end effector beneath the substrate. The vertical displacement mechanism should be operationally reliable in order to avoid damage of the substrate, the pedestal, and/or the end effector. Therefore, the vertical displacement mechanism should be configured to avoid sticking, particularly in the presence of processing materials that may lead to such sticking. It is within this context that the present invention arises.